There have been a number of prior art back-hoe hooks or ripper-tooths; see, for example U.S. Pat. Nos. 2,969,966; 3,702,712; 3,788,111; 4,038,766; 4,041,624; 5,115,583; 5,197,212; and 5,456,028. All of these prior art arrangements have one or more disadvantages as compared to Applicant's frost hook.